diff --git a/lib/browser/client.js b/lib/browser/client.js
index 7c656e011..df478e64d 100644
--- a/lib/browser/client.js
+++ b/lib/browser/client.js
@@ -62,7 +62,6 @@ Client.initOptions = function initOptions(options) {
     region: 'oss-cn-hangzhou',
     internal: false,
     secure: false,
-    timeout: 60000, // 60s
     bucket: null,
     endpoint: null,
     cname: false,
@@ -75,7 +74,9 @@ Client.initOptions = function initOptions(options) {
   opts.accessKeyId = opts.accessKeyId.trim();
   opts.accessKeySecret = opts.accessKeySecret.trim();
 
-  opts.timeout = ms(opts.timeout);
+  if (opts.timeout) {
+    opts.timeout = ms(opts.timeout);
+  }
 
   if (opts.endpoint) {
     opts.endpoint = setEndpoint(opts.endpoint);
@@ -307,17 +308,30 @@ proto.createRequest = function createRequest(params) {
 
 proto.request = function* request(params) {
   var reqParams = this.createRequest(params);
-  var result = yield this.urllib.request(reqParams.url, reqParams.params);
-  debug('response %s %s, got %s, headers: %j', params.method, reqParams.url, result.status, result.headers);
-  if (params.successStatuses && params.successStatuses.indexOf(result.status) === -1) {
-    var err = yield* this.requestError(result);
+  var result;
+  var reqErr;
+  try {
+    result = yield this.urllib.request(reqParams.url, reqParams.params);
+    debug('response %s %s, got %s, headers: %j', params.method, reqParams.url, result.status, result.headers);
+  } catch (err) {
+    reqErr = err;
+  }
+  var err
+  if (result && params.successStatuses && params.successStatuses.indexOf(result.status) === -1) {
+    err = yield this.requestError(result);
     if (err.code === 'RequestTimeTooSkewed') {
-      this.amendTimeSkewed  = +new Date(err.serverTime) - new Date()
-      return  yield* this.request(params);
+      this.amendTimeSkewed = +new Date(err.serverTime) - new Date()
+      return yield this.request(params);
     }
     err.params = params;
+  } else if (reqErr) {
+    err = yield this.requestError(reqErr);
+  }
+
+  if (err) {
     throw err;
   }
+
   if (params.xmlResponse) {
     result.data = yield this.parseXML(result.data);
   }
@@ -446,24 +460,31 @@ proto.parseXML = function parseXMLThunk(str) {
 proto.requestError = function* requestError(result) {
   var err;
   if (!result.data || !result.data.length) {
-    // HEAD not exists resource
-    if (result.status === 404) {
-      err = new Error('Object not exists');
-      err.name = 'NoSuchKeyError';
-      err.status = 404;
-      err.code = 'NoSuchKey';
-    } else if (result.status === 412) {
-      err = new Error('Pre condition failed');
-      err.name = 'PreconditionFailedError';
-      err.status = 412;
-      err.code = 'PreconditionFailed';
-    } else {
-      err = new Error('Unknow error, status: ' + result.status);
-      err.name = 'UnknowError';
+    if (result.status === -1 || result.status === -2) { //-1 is net error , -2 is timeout
+      err = new Error(result.message);
+      err.name = result.name;
       err.status = result.status;
+      err.code = result.name;
+    } else {
+      // HEAD not exists resource
+      if (result.status === 404) {
+        err = new Error('Object not exists');
+        err.name = 'NoSuchKeyError';
+        err.status = 404;
+        err.code = 'NoSuchKey';
+      } else if (result.status === 412) {
+        err = new Error('Pre condition failed');
+        err.name = 'PreconditionFailedError';
+        err.status = 412;
+        err.code = 'PreconditionFailed';
+      } else {
+        err = new Error('Unknow error, status: ' + result.status);
+        err.name = 'UnknowError';
+        err.status = result.status;
+      }
+      err.requestId = result.headers['x-oss-request-id'];
+      err.host = '';
     }
-    err.requestId = result.headers['x-oss-request-id'];
-    err.host = '';
   } else {
     var message = String(result.data);
     debug('request response error data: %s', message);
diff --git a/lib/browser/multipart.js b/lib/browser/multipart.js
index e5ed3724f..34a8d1e0b 100644
--- a/lib/browser/multipart.js
+++ b/lib/browser/multipart.js
@@ -138,8 +138,10 @@ proto._resumeMultipart = function* _resumeMultipart(checkpoint, options) {
     // check errors after all jobs are completed
     for (var i = 0; i < results.length; i++) {
       if (results[i].isError) {
-        throw new Error(
-          'Failed to upload some parts with error: ' + results[i].error.toString());
+          var error = results[i].error;
+          error.partNum = i;
+          error.message = 'Failed to upload some parts with error: ' + results[i].error.toString() + " part_num: "+ i;
+          throw error;
       }
     }
   }
diff --git a/lib/client.js b/lib/client.js
index 679922b6e..9ca4db12a 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -305,13 +305,26 @@ proto.createRequest = function createRequest(params) {
 
 proto.request = function* request(params) {
   var reqParams = this.createRequest(params);
-  var result = yield this.urllib.request(reqParams.url, reqParams.params);
-  debug('response %s %s, got %s, headers: %j', params.method, reqParams.url, result.status, result.headers);
-  if (params.successStatuses && params.successStatuses.indexOf(result.status) === -1) {
-    var err = yield* this.requestError(result);
+  var result;
+  var reqErr;
+  try {
+    result = yield this.urllib.request(reqParams.url, reqParams.params);
+    debug('response %s %s, got %s, headers: %j', params.method, reqParams.url, result.status, result.headers);
+  } catch (err) {
+    reqErr = err;
+  }
+  var err;
+  if (result && params.successStatuses && params.successStatuses.indexOf(result.status) === -1) {
+    err = yield this.requestError(result);
     err.params = params;
+  } else if(reqErr) {
+    err = yield this.requestError(reqErr);
+  }
+
+  if (err) {
     throw err;
   }
+
   if (params.xmlResponse) {
     result.data = yield this.parseXML(result.data);
   }
@@ -440,24 +453,31 @@ proto.parseXML = function parseXMLThunk(str) {
 proto.requestError = function* requestError(result) {
   var err;
   if (!result.data || !result.data.length) {
-    // HEAD not exists resource
-    if (result.status === 404) {
-      err = new Error('Object not exists');
-      err.name = 'NoSuchKeyError';
-      err.status = 404;
-      err.code = 'NoSuchKey';
-    } else if (result.status === 412) {
-      err = new Error('Pre condition failed');
-      err.name = 'PreconditionFailedError';
-      err.status = 412;
-      err.code = 'PreconditionFailed';
-    } else {
-      err = new Error('Unknow error, status: ' + result.status);
-      err.name = 'UnknowError';
+    if (result.status === -1 || result.status === -2) { //-1 is net error , -2 is timeout
+      err = new Error(result.message);
+      err.name = result.name;
       err.status = result.status;
+      err.code = result.name;
+    } else {
+      // HEAD not exists resource
+      if (result.status === 404) {
+        err = new Error('Object not exists');
+        err.name = 'NoSuchKeyError';
+        err.status = 404;
+        err.code = 'NoSuchKey';
+      } else if (result.status === 412) {
+        err = new Error('Pre condition failed');
+        err.name = 'PreconditionFailedError';
+        err.status = 412;
+        err.code = 'PreconditionFailed';
+      }else {
+        err = new Error('Unknow error, status: ' + result.status);
+        err.name = 'UnknowError';
+        err.status = result.status;
+      }
+      err.requestId = result.headers['x-oss-request-id'];
+      err.host = '';
     }
-    err.requestId = result.headers['x-oss-request-id'];
-    err.host = '';
   } else {
     var message = String(result.data);
     debug('request response error data: %s', message);
diff --git a/lib/multipart.js b/lib/multipart.js
index 927a8c152..91af58681 100644
--- a/lib/multipart.js
+++ b/lib/multipart.js
@@ -137,8 +137,10 @@ proto._resumeMultipart = function* _resumeMultipart(checkpoint, options) {
     // check errors after all jobs are completed
     for (var i = 0; i < results.length; i++) {
       if (results[i].isError) {
-        throw new Error(
-          'Failed to upload some parts with error: ' + results[i].error.toString());
+          var error = results[i].error;
+          error.partNum = i;
+          error.message = 'Failed to upload some parts with error: ' + results[i].error.toString() + " part_num: "+ i;
+          throw error;
       }
     }
   }
diff --git a/shims/xhr.js b/shims/xhr.js
index f2163ab88..07bc30bfc 100644
--- a/shims/xhr.js
+++ b/shims/xhr.js
@@ -138,6 +138,10 @@ exports.requestWithCallback = function requestWithCallback(url, args, callback)
     lookup: args.lookup,
   };
 
+  if (args.timeout) {
+    options.timeout = args.timeout;
+  }
+
   var sslNames = [
     'pfx',
     'key',
@@ -644,6 +648,18 @@ exports.requestWithCallback = function requestWithCallback(url, args, callback)
   if (typeof(window) === 'undefined') {
     // start connect timer just after `request` return, and just in nodejs environment
     startConnectTimer();
+  } else {
+    req.on('timeout', function () {
+      if (statusCode === -1) {
+        statusCode = -2;
+      }
+      var msg = 'Connect timeout for ' + connectTimeout + 'ms';
+      var errorName = 'ConnectionTimeoutError';
+      __err = new Error(msg);
+      __err.name = errorName;
+      __err.requestId = reqId;
+      abortRequest();
+    });
   }
 
   function abortRequest() {
@@ -721,7 +737,8 @@ exports.requestWithCallback = function requestWithCallback(url, args, callback)
   });
 
   req.on('error', function (err) {
-    if (err.name === 'Error') {
+    //TypeError for browser fetch api, Error for browser xmlhttprequest api
+    if (err.name === 'Error' || err.name === 'TypeError') {
       err.name = connected ? 'ResponseError' : 'RequestError';
     }
     err.message += ' (req "error")';
diff --git a/test/browser.tests.js b/test/browser.tests.js
index adb901964..8b3e5b666 100644
--- a/test/browser.tests.js
+++ b/test/browser.tests.js
@@ -767,7 +767,7 @@ describe('browser', function () {
               return function (done) {
                 assert.equal(true, res && Object.keys(res).length !== 0);
                 done();
-              }
+              };
             }
           }
         );
@@ -775,33 +775,35 @@ describe('browser', function () {
         assert.equal(result.res.status, 200);
       });
 
-      // it('should upload file using multipart upload with exception', function* () {
-      //   // create a file with 1M random data
-      //   var fileContent = Array(1024*1024).fill('a').join('')
-      //   var file = new File([fileContent], 'multipart-upload-file');
-      //
-      //   var name = prefix + 'multipart/upload-file-exception';
-      //
-      //   var stubUploadPart = sinon.stub(this.store, '_uploadPart');
-      //   stubUploadPart.throws("TestUploadPartException");
-      //
-      //
-      //   var error_msg = "";
-      //   try {
-      //     yield this.store.multipartUpload(name, file, {
-      //       progress: function () {
-      //         return function (done) {
-      //           done();
-      //         };
-      //       }
-      //     });
-      //   } catch (err) {
-      //     error_msg = err.toString();
-      //   }
-      //   assert.equal(error_msg,
-      //     "Error: Failed to upload some parts with error: TestUploadPartException");
-      //   this.store._uploadPart().restore();
-      // });
+      it('should upload file using multipart upload with exception', function* () {
+        // create a file with 1M random data
+        var fileContent = Array(1024*1024).fill('a').join('')
+        var file = new File([fileContent], 'multipart-upload-file');
+
+        var name = prefix + 'multipart/upload-file-exception';
+
+        var stubUploadPart = sinon.stub(this.store, '_uploadPart');
+        stubUploadPart.throws("TestUploadPartException");
+
+        var error_msg = "";
+        var partNum;
+        try {
+          yield this.store.multipartUpload(name, file, {
+            progress: function () {
+              return function (done) {
+                done();
+              };
+            }
+          });
+        } catch (err) {
+          error_msg = err.message;
+          partNum = err.partNum;
+        }
+        assert.equal(error_msg,
+          "Failed to upload some parts with error: TestUploadPartException part_num: 0");
+        assert.equal(partNum, 0);
+        this.store._uploadPart.restore();
+      });
     });
   });
 
@@ -835,4 +837,56 @@ describe('browser', function () {
       timemachine.reset();
     })
   });
+
+  describe('request err', function() {
+    before(function* () {
+      var ossConfig = {
+        region: stsConfig.region,
+        accessKeyId: stsConfig.Credentials.AccessKeyId,
+        accessKeySecret: stsConfig.Credentials.AccessKeySecret,
+        stsToken: stsConfig.Credentials.SecurityToken,
+        bucket: stsConfig.bucket,
+        timeout: 1
+      };
+      this.store = oss(ossConfig);
+    });
+    it('request timeout exception', function* () {
+      var fileContent = Array(1024*1024).fill('a').join('')
+      var file = new File([fileContent], 'multipart-upload-file');
+
+      var name = prefix + 'multipart/upload-file-timeout';
+
+      var timeout_err = "";
+      try {
+        yield this.store.multipartUpload(name, file);
+      } catch (err) {
+        timeout_err = err;
+      }
+      assert.equal(true, timeout_err && Object.keys(timeout_err).length !== 0);
+      assert.equal(timeout_err.status, -2);
+    });
+
+    it('request net exception', function* () {
+      var fileContent = Array(1024*1024).fill('a').join('')
+      var file = new File([fileContent], 'multipart-upload-file');
+
+      var name = prefix + 'multipart/upload-file-timeout';
+      var stubNetError = sinon.stub(this.store.urllib, 'request');
+      var netErr = new Error('TestNetErrorException');
+      netErr.status = -1;
+      netErr.code = 'RequestError';
+      netErr.name = 'RequestError';
+      stubNetError.throws(netErr);
+      var net_err = "";
+      try {
+        yield this.store.multipartUpload(name, file);
+      } catch (err) {
+        net_err = err;
+      }
+      assert.equal(true, net_err && Object.keys(net_err).length !== 0);
+      assert.equal(net_err.status, -1);
+
+      this.store.urllib.request.restore();
+    });
+  });
 });
diff --git a/test/multipart.test.js b/test/multipart.test.js
index f3914ca13..fe055518d 100644
--- a/test/multipart.test.js
+++ b/test/multipart.test.js
@@ -235,7 +235,6 @@ describe('test/multipart.test.js', function () {
       var fileName = yield utils.createTempFile('multipart-upload-file', 1024 * 1024);
 
       var name = prefix + 'multipart/upload-file-exception';
-      var progress = 0;
       var clientTmp = oss(config);
       clientTmp.useBucket(this.bucket, this.region);
 
@@ -244,13 +243,17 @@ describe('test/multipart.test.js', function () {
 
 
       var error_msg = "";
+      var partNum;
       try {
         yield clientTmp.multipartUpload(name, fileName);
       } catch (err) {
-        error_msg = err.toString();
+        error_msg = err.message;
+        partNum = err.partNum;
       }
       assert.equal(error_msg,
-        "Error: Failed to upload some parts with error: TestUploadPartException");
+        "Failed to upload some parts with error: TestUploadPartException part_num: 0");
+      assert.equal(partNum, 0);
+      clientTmp._uploadPart.restore();
     });
 
     it('should upload web file using multipart upload', function* () {
@@ -415,4 +418,54 @@ describe('test/multipart.test.js', function () {
     });
 
   });
+
+  describe('request error', function() {
+
+    it('request timeout exception', function* () {
+      var fileName = yield utils.createTempFile('multipart-upload-file', 1024 * 1024);// 1m
+      var name = prefix + 'multipart/upload-file';
+
+      var stubNetError = sinon.stub(this.store.urllib, 'request');
+      var netErr = new Error('TestTimeoutErrorException');
+      netErr.status = -2;
+      netErr.code = 'ConnectionTimeoutError';
+      netErr.name = 'ConnectionTimeoutError';
+      stubNetError.throws(netErr);
+      var timeout_err;
+      try {
+        yield this.store.multipartUpload(name, fileName);
+      } catch (err) {
+        timeout_err = err;
+      }
+
+      assert.equal(true, timeout_err && Object.keys(timeout_err).length !== 0);
+      assert.equal(timeout_err.status, -2);
+      this.store.urllib.request.restore();
+    });
+
+    it('request net exception', function* () {
+      var fileName = yield utils.createTempFile('multipart-upload-file', 1024 * 1024);// 1m
+      var name = prefix + 'multipart/upload-file';
+
+      var stubNetError = sinon.stub(this.store.urllib, 'request');
+      var netErr = new Error('TestNetErrorException');
+      netErr.status = -1;
+      netErr.code = 'RequestError';
+      netErr.name = 'RequestError';
+      stubNetError.throws(netErr);
+
+      var net_err;
+      try {
+        yield this.store.multipartUpload(name, fileName);
+      } catch (err) {
+        net_err = err;
+      }
+
+      assert.equal(true, net_err && Object.keys(net_err).length !== 0);
+      assert.equal(net_err.status, -1);
+
+      this.store.urllib.request.restore();
+    });
+  });
+
 });